I just purchased a Dell XPS 13, running Windows 8.

I have two external LaCie hard drives.

Drive 1 is used with a Lenovo X120e running Windows 7.

Drive 2 has two partitions, one exclusively for my Macbook Pro running 10.9.5 and the other smaller partition is used for moving files between the Lenovo and the Macbook.

When I connect Drive 1 to the XPS 13, nothing happens. It doesn't spin nor does it show up in the device manager.

If I switch it back to the Lenovo it works fine.

When I connect Drive 2 to the XPS 13 (to the same USB port and using the same cable), it spins and is detected.

So the port is working, the drivers are working and the cable is working and Drive 1 works when connected to the Lenovo running Windows 7.

How do I get the XPS 13 to recognize Drive 1? There must be some way to do this without formatting anew.

Are your LaCie drives identical?

Did you try another USB port on the XPS-13?

Are the LaCie drives powered or do they use the USB port for power?

The drives are identical.

I tried both ports on the XPS-13 with the same results.

The drives are AC powered.

Is the drive visible in the BIOS or safe mode on the XPS-13?

You might also try swapping the power connection to the drive from the one that works.